Semiconductor light emitting device

Abstract

Provided is a semiconductor device having high bonding properties and high air tightness, as well as high reliability and high environmental resistance. The semiconductor light-emitting device comprises: a semiconductor light-emitting element; a substrate on which the semiconductor light-emitting element is mounted and which has a substrate bonding surface covered by a substrate metal layer; and a light-transmitting cap having a window portion for transmitting radiated light from the semiconductor light-emitting element and a flange having a flange bonding surface with a circular inner edge, the light-transmitting cap having a space for accommodating the semiconductor light-emitting element and being sealed and bonded to the substrate, the surface of the flange bonding surface being a metal layer, the flange bonding surface having a flat portion and a pressing ring, the pressing ring being an annular convex portion protruding from the flat portion and concentric with the circular inner edge, and the substrate metal layer and the flange metal layer, the substrate metal layer and the top of the pressing ring are bonded together by a bonding component at a certain interval.

Description

Technical Field

[0001] The present invention relates to a semiconductor light emitting device, and in particular to a semiconductor light emitting device having a semiconductor light emitting element that radiates ultraviolet light sealed therein. Background Art

[0002] Conventionally, there are known semiconductor devices in which semiconductor elements are enclosed in semiconductor packages. In the case of semiconductor light emitting modules, a transparent window member such as glass is bonded to a support body on which a semiconductor light emitting element is mounted to form an airtight seal, wherein the transparent window member allows light from the light emitting element to pass through.

[0003] For example, Patent Documents 1 and 2 disclose semiconductor light emitting modules formed by bonding a substrate having a recess for accommodating a semiconductor light emitting element and a window member.

[0004] Patent Documents 3 and 4 disclose ultraviolet light emitting devices in which a mounting substrate on which an ultraviolet light emitting element is mounted, a spacer, and a cover made of glass are bonded together.

[0005] Prior art literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2015-18873

[0007] Patent Document 2: Japanese Patent Application Publication No. 2018-93137

[0008] Patent Document 3: Japanese Patent Application Publication No. 2016-127255

[0009] Patent Document 4: Japanese Patent Application Publication No. 2016-127249 Summary of the invention

[0010] However, it is required to further improve the sealing and bonding reliability between the substrate and the window member. Semiconductor light emitting elements that radiate ultraviolet light, especially AlGaN-based semiconductor light emitting elements, are prone to deterioration if their airtightness is not high enough, and semiconductor devices equipped with such semiconductor light emitting elements require high airtightness.

[0011] In addition, AlGaN-based crystals will degrade due to moisture. In particular, the shorter the emission wavelength, the more Al components there are, and the easier it is to degrade. Therefore, as an airtight structure to prevent moisture from entering the interior of the package that accommodates the light-emitting element, a structure that uses metal bonding parts to make the substrate and the glass cover airtight is adopted. However, when used in a humid environment or a water supply environment, there is a problem that the airtightness is not high enough.

[0012] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a semiconductor device having high bonding properties and high airtightness, as well as high reliability and high environmental resistance.

[0013] A semiconductor light-emitting device in one embodiment of the present invention comprises: a semiconductor light-emitting element; a substrate, which carries the semiconductor light-emitting element and has a substrate bonding surface covered by a substrate metal layer; and a translucent cap, which has a window portion for transmitting radiated light from the semiconductor light-emitting element, and a flange having a flange bonding surface with a circular inner edge, the translucent cap having a space for accommodating the semiconductor light-emitting element and being sealed and bonded to the substrate, the surface of the flange bonding surface is a metal layer, the flange bonding surface has a flat portion and a pressing ring, the pressing ring is an annular convex portion protruding from the flat portion and concentric with the inner edge of the circle, and with respect to the substrate metal layer and the flange metal layer, the substrate metal layer and the top of the pressing ring are bonded together by a bonding component at a certain interval. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1A It is a plan view schematically showing the upper surface of the semiconductor light emitting device 10 according to the first embodiment.

[0015] Figure 1B It is a diagram schematically showing a side surface of the semiconductor light emitting device 10 .

[0016] Figure 1C It is a plan view schematically showing the back surface of the semiconductor light emitting device 10 .

[0017] Figure 1D 1 is a diagram schematically showing the internal structure of the semiconductor light emitting device 10 .

[0018] Figure 1E It is a perspective view schematically showing a 1 / 4 portion of the light-transmitting cap 13 according to the first embodiment.

[0019] Figure 2 is schematically shown along Figure 1A sectional view of the cross section of the semiconductor light emitting device 10 taken along line AA.

[0020] Figure 3A It is a cross-sectional view schematically showing a state before the substrate 11 and the light-transmitting cap 13 are joined together.

[0021] Figure 3B It is a cross-sectional view schematically showing a state where the substrate 11 and the light-transmitting cap 13 are bonded together.

[0022] Figure 4A This is a partially enlarged cross-sectional view showing an enlarged cross section of a joining portion between the base plate 11 and the flange portion 13B.

[0023] Figure 4B This is a partially enlarged cross-sectional view showing an enlarged cross section of a joining portion between the base plate 11 and the flange portion 13B.

[0024] Figure 5A It is a plan view schematically showing the upper surface of the semiconductor light emitting device 30 according to the second embodiment.

[0025] Figure 5B It is a diagram schematically showing a side surface of the semiconductor light emitting device 30 .

[0026] Figure 5C It is a diagram schematically showing the back side of the semiconductor light emitting device 30 .

[0027] Figure 5D Schematic diagram of the internal structure of the semiconductor light emitting device 30 .

[0028] Figure 5E It is a perspective view schematically showing a 1 / 4 portion of the light-transmitting cap 13 according to the second embodiment.

[0029] Figure 6 is schematically shown along Figure 5A BB line is a cross-sectional view of the semiconductor light emitting device 30 .

[0030] Fig. 7A This is a partial enlarged cross-sectional view showing an enlarged view of a joining portion between the base plate 11 and the flange portion 13B.

[0031] Figure 7B It is a partially enlarged cross-sectional view of the bonding portion, showing a state where the top of the pressing ring 21A abuts against the substrate metal layer 12 .

[0032] Fig. 8A It is a plan view schematically showing a modification of the second embodiment.

[0033] Figure 8B It is a plan view showing an enlarged corner of a flange portion 13B according to a modification of the second embodiment.

[0034] Figure 8C It is a plan view showing an enlarged corner of a flange portion 13B according to a modification of the second embodiment.

[0035] Fig. 9 It is a plan view showing another modified example of the second embodiment.

[0036] Fig.10 It is a partially enlarged cross-sectional view showing a case where the bottom surface of the flange portion 13B is a flat surface.

[0037] Fig.11 1 is a plan view showing a state in which an auxiliary pressing ring 21C, which is a circular annular convex portion concentric with the pressing ring 21A, is provided on the outer side of the pressing ring 21A.

[0038] Description of symbols

[0039] 10, 30 Semiconductor light-emitting device

[0040] 11 base plate

[0041] 12. Substrate metal layer

[0042] 13 Translucent Cap

[0043] 13A Window

[0044] 13B Flange

[0045] 13C, 13D convex part

[0046] 21 Flange metal layer

[0047] 21A Press Ring

[0048] 21B Auxiliary pressing part

[0049] 21B1, 21B2, 21B3 Auxiliary pressing element

[0050] 21C Auxiliary compression ring

[0051] 22 Cap bonding layer

[0052] C Circle Center

[0053] CC Concentric Circles

[0054] GA, GB gap

[0055] DL Diagonal

[0056] JI medial junction area

[0057] JM Middle Joint Region

[0058] JN, JN1, JN2 Narrow joint area

[0059] JO Outer joint area DETAILED DESCRIPTION

[0060] The preferred embodiments of the present invention will be described below, but they can also be appropriately changed and combined. In addition, in the following description and drawings, the same reference numerals are used to mark substantially the same or equivalent parts for description.

[0061] [First embodiment]

[0062] Figure 1A It is a plan view schematically showing the upper surface of the semiconductor light emitting device 10 according to the first embodiment of the present invention. Figure 1B It is a diagram schematically showing a side surface of the semiconductor light emitting device 10 . Figure 1CIt is a plan view schematically showing the back surface of the semiconductor light emitting device 10 . Figure 1D Schematically shows the internal structure of the semiconductor light emitting device 10. Figure 2 is schematically shown along Figure 1A sectional view of the cross section of the semiconductor light emitting device 10 taken along line AA.

[0063] like Figure 1A and Figure 1B As shown, the semiconductor light emitting device 10 is formed by joining a rectangular plate-shaped substrate 11 and a light-transmitting window made of a semi-spherical glass material, i.e., a light-transmitting cap 13. In more detail, a circular ring-shaped metal layer 12 (hereinafter also referred to as substrate metal layer 12) is formed on the upper surface of the substrate 11 and joined to the light-transmitting cap 13.

[0064] In addition, the side surfaces of the substrate 11 are shown to be parallel to the x-direction and the y-direction, and the upper surface of the substrate 11 is shown to be parallel to the xy plane.

[0065] like Figure 1E and Figure 2 As shown, the light-transmitting cap 13 is composed of a semi-spherical dome portion 13A and a flange portion 13B provided at the bottom of the dome portion 13A. Figure 1E It is a perspective view schematically showing a 1 / 4 portion of the light-transmitting cap 13 .

[0066] The flange portion 13B has a circular ring plate shape. A flange metal layer 21 is fixed to the bottom surface of the flange portion 13B to form a flange bonding surface. The flange metal layer 21 is bonded to the substrate metal layer 12 via the bonding layer 22, thereby ensuring the airtightness between the substrate 11 and the light-transmitting cap 13.

[0067] The substrate 11 is a ceramic substrate that is impermeable to air. For example, aluminum nitride (AlN) having high thermal conductivity and excellent airtightness is used. In addition, other ceramics having excellent airtightness such as alumina (Al2O3) can be used as the base material of the substrate 11.

[0068] The light-transmitting cap 13 is made of glass that transmits the radiated light from the light-emitting element 15 disposed in the semiconductor light-emitting device 10. For example, quartz glass or borosilicate glass can be preferably used.

[0069] As the sealing gas in the semiconductor light emitting device 10 , dry nitrogen gas, air, or the like can be used, or the inside can be made a vacuum.

[0070] like Figure 1DAs shown, a first wiring electrode (e.g., an anode electrode) 14A and a second wiring electrode (e.g., a cathode electrode) 14B (hereinafter referred to as wiring electrodes 14 when not specifically distinguished) as wiring electrodes in the semiconductor light emitting device 10 are provided on the substrate 11. A semiconductor light emitting element 15 such as a light emitting diode (LED) or a semiconductor laser is bonded to the first wiring electrode 14A via a metal bonding layer 15A, and a bonding pad 15B of the light emitting element 15 is electrically connected to the second wiring electrode 14B via a bonding wire 18C.

[0071] The light emitting element 15 is a semiconductor light emitting element (LED) of aluminum gallium nitride (AlGaN) system having a semiconductor structural layer including an n-type semiconductor layer, a light emitting layer and a p-type semiconductor layer. In addition, the semiconductor structural layer of the light emitting element 15 is formed (bonded) on a conductive supporting substrate (silicon: Si) via a reflective layer.

[0072] The light emitting element 15 has an anode electrode (not shown) on the surface opposite to the surface on which the semiconductor structure layer is bonded to the support substrate (also referred to as the back surface of the light emitting element 15), which is electrically connected to the first wiring electrode 14A on the substrate 11. In addition, the light emitting element 15 has a cathode electrode (cathode electrode pad 15B) on the surface opposite to the surface on which the support substrate is bonded to the semiconductor structure layer (also referred to as the surface of the light emitting element 15), which is electrically connected to the second wiring electrode 14B via a bonding wire.

[0073] The light emitting element 15 is preferably an aluminum nitride-based light emitting element that emits ultraviolet light at a wavelength of 265 to 415 nm. Specifically, a light emitting element having a central emission wavelength of 265 nm, 275 nm, 355 nm, 365 nm, 385 nm, 405 nm, or 415 nm is used.

[0074] The semiconductor crystal constituting the aluminum nitride-based ultraviolet radiating light-emitting element (UV-LED element) has a high Al content and is easily oxidized and degraded by oxygen (O 2 ) or water (H 2 O).

[0075] Furthermore, a protective element 16 which is a Zener diode (ZD) connected to the first wiring electrode 14A and the second wiring electrode 14B is provided on the substrate 11 to prevent electrostatic destruction of the light emitting element 15 .

[0076] like Figure 1C As shown, a first mounting electrode 17A and a second mounting electrode 17B (hereinafter referred to as mounting electrodes 17 unless otherwise specifically distinguished) connected to the first wiring electrode 14A and the second wiring electrode 14B, respectively, are provided on the back surface of the substrate 11. Specifically, the first wiring electrode 14A and the second wiring electrode 14B are connected to the first mounting electrode 17A and the second mounting electrode 17B, respectively, via metal vias 18A and 18B made of, for example, copper (Cu).

[0077] Reference Figure 2 When the semiconductor light emitting device 10 is mounted on a wiring circuit substrate (not shown), a voltage is applied to the first mounting electrode 17A and the second mounting electrode 17B, so that the light emitting element 15 emits light, and the radiated light LE from the surface (light extraction surface) of the light emitting element 15 is radiated to the outside through the light-transmitting cap 13.

[0078] Next, the joining of the substrate 11 and the flange portion 13B of the light-transmitting cap 13 will be described.

[0079] (Light-transmitting cap 13 and flange portion 13B)

[0080] In addition, if Figure 1A and Figure 1B As shown in the figure, the light-transmitting cap 13 includes a dome portion 13A, which is a semi-spherical window portion, and a flange portion 13B provided at the bottom of the dome portion 13A. The flange portion 13B has a cylindrical shape. In more detail, the bottom surface of the flange portion 13B has a circular ring shape (center: C) concentric with the center of the dome portion 13A. That is, the outer edge (outer periphery) of the flange portion 13B is concentric with the inner edge (inner periphery) of the flange portion 13B.

[0081] Figure 3A 1 is a cross-sectional view schematically showing the state before the substrate 11 and the light-transmitting cap 13 are joined. In the central part of the annular bottom surface of the flange portion 13B in the radial direction (width direction), a convex portion 13C is formed along the circumference of a concentric circle with the bottom surface of the flange portion 13B (flange joining surface). That is, the bottom surface of the flange portion 13B is formed with a flat surface and a convex portion 13C (hereinafter sometimes referred to as an annular convex portion) protruding from the flat surface. In addition, the cross-sectional shape of the annular convex portion 13C perpendicular to the circumference of the concentric circle is semicircular, but is not limited to this. For example, it can also be rectangular or trapezoidal.

[0082] (Flange Metal Layer 21)

[0083] Furthermore, a metal layer 21 is fixed to the bottom surface of the flange portion 13B. The convex portion 13C and the flange metal layer 21 form a pressing ring 21A, which is an annular convex portion whose surface is covered with metal, along the bottom surface of the flange portion 13B.

[0084] (Substrate metal layer 12)

[0085] like Figure 1A and Figure 1D As shown, a metal ring body having a circular ring shape, namely a substrate metal layer 12, is fixed on the substrate 11 to form a substrate bonding surface. In more detail, the bonding area of ​​the substrate 11 to which the substrate metal layer 12 is fixed is flat, and the substrate metal layer 12 has a shape (i.e., a circular ring shape) and size corresponding to the bottom surface of the flange portion 13B.

[0086] The base metal layer 12 has a size that includes the entire flange metal layer 21 on the bottom surface of the flange portion 13B. The base metal layer 12 is formed to be electrically insulated from the first wiring electrode 14A, the second wiring electrode 14B, the light emitting element 15, and the protective element 16, and to surround them.

[0087] A circular bonding member is placed on the circular substrate metal layer 12, heated, and a force F is applied to the transparent cap 13 and pressed, so that Figure 3B As shown, a ring-shaped cap bonding layer 22 to which the light-transmitting cap 13 is bonded is formed on the substrate 11 .

[0088] The substrate metal layer 12 has a structure in which tungsten, nickel, and gold are sequentially stacked on the substrate 11 (W / Ni / Au) or a structure in which nickel chromium, gold, nickel, and gold are sequentially stacked (NiCr / Au / Ni / Au).

[0089] The metal layer 21 on the bottom surface of the flange portion 13B has a structure in which chromium, nickel, and gold are stacked in sequence (Cr / Ni / Au) or a structure in which titanium, palladium, copper, nickel, and gold are stacked in sequence (Ti / Pd / Cu / Ni / Au).

[0090] The bonding component of the cap bonding layer 22 is, for example, a ring-shaped AuSn (gold tin) sheet without flux, and a component containing 22wt% Sn (melting temperature: about 300°C) is used. Au (10-30nm) layers can also be provided on both surfaces of the gold-tin alloy sheet. This prevents oxidation of the AuSn alloy and improves airtightness. In addition, the Au layer dissolves in the cap bonding layer 22 during melting and solidification (bonding).

[0091] [Method of Manufacturing Light Emitting Device 10]

[0092] Next, a method for manufacturing the light emitting device 10 will be described in detail and specifically.

[0093] (Component bonding process)

[0094] First, AuSn volatile solder paste is applied to the first wiring electrode 14A of the substrate 11. Next, the light emitting element 15 is placed on the volatile solder paste, and the substrate is heated to 300°C to melt and solidify the AuSn, thereby bonding the light emitting element 15 to the first wiring electrode 14A. In addition, when the protective element 16 is mounted, the bonding of the protective element 16 is performed simultaneously. At this time, the flux contained in the volatile solder paste is almost volatilized.

[0095] Next, the bonding pad 15B of the upper electrode of the light emitting element 15 and the second wiring electrode 14B are electrically connected by the bonding wire 18C (Au wire).

[0096] (Flux additional volatilization process)

[0097] The substrate 11 to which the light emitting element 15 was bonded as described above was placed on a heater and heated at an annealing temperature of 320° C. for 20 seconds in a nitrogen atmosphere to volatilize the residue (flux) of the volatile solder paste.

[0098] The lower limit of the additional volatilization temperature is preferably 300°C or higher (i.e., the melting temperature of the bonding layer 22) at which the residue (flux) is volatilized. The upper limit of the additional volatilization temperature is preferably lower than the temperature at which the bonding layer 22 does not remelt, for example, 330°C or lower.

[0099] (Excimer light cleaning process)

[0100] The substrate 11 after the additional volatilization was placed on an excimer light irradiation device and irradiated with 2000 mJ / cm 2 The above excimer light is used to decompose and remove the residue (flux) adsorbed on the surfaces of the substrate 11 and the light emitting element 15 .

[0101] (Cap joining process)

[0102] The substrate 11 and the light-transmitting cap 13 after the excimer light cleaning step were placed on a cap bonding device, and then the atmosphere of the substrate 11 and the light-transmitting cap 13 was made into a vacuum state, and a heating treatment (annealing treatment) was performed at a temperature of 275° C. for 15 minutes.

[0103] Next, the atmosphere of the substrate 11 and the light-transmitting cap 13 is filled with a packaging gas, i.e., dry nitrogen (N2), at a pressure of 1 atmosphere (101.3 kPa). Next, a ring-shaped AuSn sheet (a bonding component of the cap bonding layer 22) is placed on the substrate metal layer 12 of the substrate 11, and the light-transmitting cap 13 is placed on the ring-shaped AuSn sheet and pressed.

[0104] like Figure 3A As shown, the light-transmitting cap 13 is pressed against the annular AuSn sheet and heated to 320° C. By heating, the AuSn sheet melts from the portion that is in close contact with the pressing ring 21A toward the inside and outside, so that a small amount of gold in the metal layers 12 and 21 melts and solidifies, or solidifies by cooling. As described above, the substrate 11 and the light-transmitting cap 13 are bonded, and the semiconductor light-emitting device 10 is completed.

[0105] [Joining portion between substrate 11 and flange portion 13B]

[0106] By joining the substrate 11 and the flange portion 13B, as shown in FIG. Figure 4AAs shown in FIG. 1 , the annular region formed by the pressing ring 21A pressing the melted AuSn to expand it forms the narrow joint region JN. In addition, an inner joint region JI and an outer joint region JO are formed on the inner and outer sides of the pressing ring 21A, that is, on the inner and outer sides of the narrow joint region JN, respectively, when viewed from above (when viewed from a direction (z direction) perpendicular to the flange portion 13B).

[0107] In this case, the top of the pressing ring 21A and the substrate metal layer 12 are joined with a certain gap (gap) GA within the entire circumference of the top of the pressing ring 21A. In addition, below, for easy description and understanding, the widths of the inner area JI, the narrow joint area JN, and the outer joint area JO are described using the same reference numerals (JI, JN, JO), respectively.

[0108] In addition, in the above-mentioned bonding process, the pressing ring 21A further presses the melted AuSn to expand it, and can press until the top of the pressing ring 21A abuts against the substrate metal layer 12. In this case, Figure 4B As shown, the top of the pressing ring 21A contacts the substrate metal layer 12 to form a circular connection line, that is, a circular connection portion JL that does not include a bonding component (AuSn) is formed between the pressing ring 21A and the substrate metal layer 12, and a linear airtight structure is formed in this portion.

[0109] That is, a circular airtight structure is formed in which the top of the pressing ring 21A is in close contact with the base metal layer 12. In this case, in the circular connection portion JL, the interval (gap) GA between the top of the pressing ring 21A and the base metal layer 12 is 0.

[0110] As described above, the cap bonding layer 22 is divided into three regions, namely the inner bonding region JI, the narrow bonding region JN and the outer bonding region JO, by the pressing ring 21A with the center of the pressing ring 21A as the boundary. The pressing ring 21A is a pressing portion of the bonding member and has the function of regional division and positioning of the cap bonding layer 22.

[0111] Furthermore, the pressing ring 21A has a function of preventing the bonding component from overflowing by controlling the gap (distance) GA between the top of the pressing ring 21A and the substrate metal layer 12 .

[0112] The inner joint region JI and the outer joint region JO function as fillets for the pressing ring 21A, and improve shear strength, that is, fracture strength in the lateral direction (a direction parallel to the joint surface).

[0113] Furthermore, when the gap GA=0, the narrow joint area JN is formed by the top of the pressing ring 21A and the substrate metal layer 12 at the position JL ( Figure 4B) acts as a linear airtightness formed by linear (circular) contact, and the inner joining area JI and the outer joining area JO act as a band airtightness.

[0114] Therefore, the bonded crystal portion can be thinned or eliminated, and the area of ​​the metal crystal interface that causes leakage can be minimized, thereby improving the airtightness yield.

[0115] In addition, the cap bonding layer 22 of the inner bonding area JI and the outer bonding area JO melts and solidifies toward the inside and the outside with the pressing ring 21A as the starting point, thereby preventing the generation of internal stress and preventing gaps from appearing between the metal grain boundaries forming the bonding layer 22, thereby improving the airtight yield rate.

[0116] By adopting a narrow joint area and setting it to linear airtightness or strip airtightness, the area where poor joint occurs can be reduced, thereby improving airtightness. In addition, the area of ​​the metal crystal interface that is the cause of leakage can be minimized, thereby improving airtightness. Furthermore, there is an airtight structure in the narrow joint area and on both sides thereof, thereby obtaining high airtightness reliability. In addition, further, it is possible to prevent gaps from occurring between metal grain boundaries, thereby improving airtightness.

[0117] In addition, the pressing ring 21A is preferably configured so that the widths of the inner joint area JI and the outer joint area JO are equal (ie, width JI=JO). That is, the pressing ring 21A is provided along a circle having the center of the width of the annular flange metal layer 21 (flange joint surface) as the circumference.

[0118] The wall thickness of the window portion, i.e., the dome portion 13A, of the light-transmitting cap 13 can be made uniform throughout, or the central portion (convex meniscus lens) can be thickened to narrow the light distribution, or the periphery (concave meniscus lens) can be thickened to widen the light distribution.

[0119] [Second embodiment]

[0120] Figure 5A It is a plan view schematically showing the upper surface of a semiconductor light emitting device 30 according to the second embodiment of the present invention. Figure 5B and Figure 5C The diagrams schematically show the side surface and the back surface of the semiconductor light emitting device 30 . Figure 5D Schematic diagram of the internal structure of the semiconductor light emitting device 30 . Figure 5E 1 is a perspective view schematically showing a 1 / 4 portion of the light-transmitting cap 13. Figure 6 is schematically shown along Figure 5A BB line of the semiconductor light emitting device 30 is a cross-sectional view. In addition, for the clarity of the drawings and descriptions, Figure 6A portion of one half of the light-transmitting cap 13 is shown.

[0121] like Figure 5A and Figure 5B As shown in FIG. 1 , the semiconductor light emitting device 30 is formed by joining a rectangular plate-shaped substrate 11 and a light-transmitting window, i.e., a light-transmitting cap 13, which is made of semi-spherical glass. Figure 5D As shown, a substrate metal layer 12 is formed on the upper surface of the substrate 11 and is bonded to the light-transmitting cap 13. Next, the bonding between the substrate 11 and the flange portion 13B of the light-transmitting cap 13 will be described in more detail.

[0122] (Light-transmitting cap 13 and flange portion 13B)

[0123] like Figure 5A and Figure 6 As shown, the light-transmitting cap 13 of the second embodiment includes a dome portion 13A which is a semispherical window portion and a flange portion 13B provided at the bottom of the dome portion 13A.

[0124] like Figure 5A and Figure 5E As shown, the light-transmitting cap 13 of this embodiment is different from the light-transmitting cap 13 of the first embodiment, and the flange portion 13B has a prismatic shape. In more detail, the flange portion 13B has a plate shape with a rectangular outer edge (outer periphery). Here, the case where the flange portion 13B has a square outer edge is described. In addition, the inner edge of the flange portion 13B is connected to the edge of the dome portion 13A and has a circular shape (center: C).

[0125] like Figure 5A and Figure 6 As shown, a circular protrusion 13C is formed on the bottom surface of the flange portion 13B, which is concentric with the dome portion 13A (center: C). The cross-sectional shape of the circular protrusion 13C perpendicular to the circumference of the concentric circle is semicircular, but is not limited to this. For example, it can also be rectangular or trapezoidal.

[0126] Furthermore, a semispherical convex portion 13D is provided on the diagonal line DL of the flange portion 13B having a square outer edge and outside the annular convex portion 13C at a position away from the annular convex portion 13C.

[0127] (Flange Metal Layer 21)

[0128] In addition, if Figure 6 As shown in FIG. 1 , a flange metal layer 21 is fixed to the bottom surface of the flange portion 13B. That is, the inner edge of the flange joint surface is circular, and the outer edge is rectangular.

[0129] The protrusion 13C and the flange metal layer 21 form a pressing ring 21A which is an annular protrusion along the bottom surface of the flange 13B. In addition, the surface of the protrusion 13D is covered with the flange metal layer 21, and the auxiliary pressing portion 21B is formed.

[0130] (Substrate metal layer 12)

[0131] like Figure 5A and Figure 5D As shown, a substrate metal layer 12 having a rectangular outer edge is fixed on the substrate 11, forming a substrate bonding surface. That is, the substrate metal layer 12 has a shape corresponding to the bottom surface of the flange portion 13B having a circular inner edge (inner periphery) and a rectangular outer edge. In addition, the substrate metal layer 12 has a size that includes the entire flange metal layer 21 on the bottom surface of the flange portion 13B.

[0132] The substrate metal layer 12 is formed so as to be electrically insulated from the first wiring electrode 14A, the second wiring electrode 14B, the light emitting element 15 and the protection element 16 and to surround them.

[0133] A bonding sheet, i.e., a bonding layer 22, having a shape and size corresponding to the bottom surface of the flange portion 13B is placed on the substrate metal layer 12, heated, and a force F is applied to the light-transmitting cap 13 to press it, thereby Figure 6 As shown, the substrate 11 and the light-transmitting cap 13 can be bonded. That is, the flange metal layer 21 is bonded to the substrate metal layer 12 via the bonding layer 22, thereby ensuring airtightness between the substrate 11 and the light-transmitting cap 13.

[0134] [Joining portion between substrate 11 and flange portion 13B]

[0135] Fig. 7A 1 is a partial enlarged cross-sectional view showing the junction between the substrate 11 and the flange 13B. The annular region formed by the pressing ring 21A pressing the melted AuSn to expand it through the junction between the substrate 11 and the flange 13B forms the first narrow junction region JN1. In addition, the inner junction region JI and the middle junction region JM are formed on the inner and outer sides of the pressing ring 21A, that is, on the inner and outer sides of the first narrow junction region JN1, respectively.

[0136] In the present embodiment, the inner joint region JI has an annular shape in a plan view. In addition, the middle joint region JM is formed as a band-shaped region along the direction of the diagonal line DL of the flange portion 13B.

[0137] In addition, during the bonding, the auxiliary pressing portion 21B is used to press the bonding component AuSn to expand it, thereby forming a second narrow bonding area JN2. That is, when the auxiliary pressing portion 21B is semi-spherical, a second narrow bonding area JN2 that is circular when viewed from above (when viewed from a direction perpendicular to the flange 13B) is formed on the diagonal line DL of the flange 13B and outside the pressing ring 21A.

[0138] The area inside the second narrow joint area JN2 is the middle joint area JM, and the outer joint area JO is formed outside the second narrow joint area JN2.

[0139] Next, a case where the height H2 of the auxiliary pressing portion 21B (height of the protrusion) is smaller than the height H1 of the pressing ring 21A will be described. However, the auxiliary pressing portion 21B and the pressing ring 21A may have the same height (H1=H2).

[0140] The top of the pressing ring 21A is bonded to the substrate metal layer 12 via a gap GA. In addition, the auxiliary pressing portion 21B is bonded to the substrate metal layer 12 via a gap GB, and the gap GA is smaller than the gap GB (GA <GB)。

[0141] In addition, similarly to the case of the first embodiment, in the above-mentioned bonding step, the pressing ring 21A further presses the melted AuSn to expand it, and can press until the top of the pressing ring 21A abuts against the substrate metal layer 12. In this case, Figure 7B As shown, the top of the pressing ring 21A and the substrate metal layer 12 are in direct contact to form a circular connection line, that is, a circular connection part JL not including a bonding component (AuSn) is formed between the pressing ring 21A and the substrate metal layer 12, forming a linear airtight structure.

[0142] That is, a circular airtight structure is formed in which the top of the pressing ring 21A is in close contact with the base metal layer 12. In this case, in the circular connection portion JL, the gap (S gap) GA between the top of the pressing ring 21A and the base metal layer 12 is 0.

[0143] (Function of the auxiliary pressing portion 21B)

[0144] Regarding the bonding between the substrate 11 and the flange portion 13B (i.e., the melting and solidification of the bonding component), it is preferred to bond from the location of the pressing ring 21A toward the outside of the flange 13B. However, when the flange portion 13B is rectangular, the bonding at the portion away from the pressing ring 21A, i.e., the melting and solidification of the AuSn bonding component at the corresponding portion, may lag behind that at the portion of the pressing ring 21A.

[0145] In this embodiment, the auxiliary pressing portion 21B is provided in the corner region (in the diagonal DL direction) of the flange portion 13B which is far from the pressing ring 21A, so that the bonding hysteresis in this region can be prevented, and stable bonding can be achieved within the entire surface of the flange portion 13B. In addition, by preventing the bonding hysteresis, the formation of gaps between the grain boundaries of the AuSn bonding component can also be prevented.

[0146] [Variation of the Second Embodiment]

[0147] Fig. 8A 2 is a modified example of the second embodiment, and is a top view schematically showing the structure viewed from the upper surface of the semiconductor light emitting device 30. Figure 8B 1 is a plan view showing an enlarged corner of the flange portion 13B. In the present modification, an auxiliary pressing portion 21B composed of a plurality of pressing elements 21B1, 21B2, and 21B3 is provided at the corner.

[0148] In more detail, one pressing element 21B1 is provided on the diagonal line DL of the flange portion 13B which is rectangular when viewed from above, and a plurality of (two in this modified example) pressing elements 21B2 and 21B3 are provided at positions deviating from the diagonal line DL. Thus, when the auxiliary pressing portion 21B composed of a plurality of pressing elements 21Bn (n is an integer greater than or equal to 2) is provided, it is preferred that at least one pressing element is provided on the diagonal line DL. In addition, it is preferred that the auxiliary pressing portion 21B is provided at all four corners of the flange portion 13B.

[0149] Or, if Figure 8C As shown, the plurality of pressing elements 21Bn may be arranged on the circumference of a circle CC (center: C) that is concentric with the pressing ring 21A, that is, arranged at an equal distance from the pressing ring 21A.

[0150] also, Fig. 9 2 is a plan view showing another modified example in which the auxiliary pressing portion 21B is arranged on the diagonal line DL as a part of a circular ring concentric with the pressing ring 21A and having a larger diameter than the pressing ring 21A outside the pressing ring 21A.

[0151] Alternatively, as the auxiliary pressing portion 21B, an auxiliary pressing ring which is a circular ring concentric with the pressing ring 21A and has a larger diameter than the pressing ring 21A may be provided as a whole.

[0152] In this modification, similarly to the second embodiment, internally stabilized joining can be achieved over the entire surface of the flange portion 13B.

[0153] In addition, in this embodiment, as in the first embodiment, the function of area division and positioning realized by the pressing ring 21A and the function of preventing the bonding component from overflowing are also provided. In addition, the inner bonding area JI and the middle bonding area JM function as fillets for the pressing ring 21A and have the function of increasing the shear strength and the breaking strength, which is also the same.

[0154] Furthermore, when the gap GA = 0, the narrow joint area JN functions as a linear airtight seal formed by direct contact between the top of the pressing ring 21A and the substrate metal layer 12 at the position JL and in a linear (circular when viewed from above) contact. On the other hand, the inner joint area JI and the middle joint area JM function as a band-shaped airtight seal.

[0155] [Another variation]

[0156] In the above-mentioned embodiments, the case where the outer edge of the flange portion 13B has a circular shape (first embodiment) and the case where the outer edge of the flange portion 13B has a rectangular shape (second embodiment) are described, but the outer edge of the flange portion 13B may also have a polygonal shape with n sides (n is an integer greater than 3).

[0157] In the case where the outer edge of the flange portion 13B has a circular shape or an n-gonal shape, as shown in FIG. Fig.11 As shown, an auxiliary pressing ring 21C can also be set on the outside of the pressing ring 21A as an auxiliary pressing portion 21B. The auxiliary pressing ring 21C is concentric with the pressing ring 21A and is an annular convex portion protruding from the flat portion of the bottom surface of the flange portion 13B. The diameter is larger than the diameter of the pressing ring 21A.

[0158] Furthermore, when the outer edge (outer shape) of the flange portion 13B has an n-gonal shape (n is an integer greater than or equal to 3), an auxiliary pressing ring having a circular ring concentric with the pressing ring 21A and having a larger diameter than the pressing ring 21A may be provided as the auxiliary pressing portion 21B. In particular, when the outer shape of the flange portion 13B has a shape with low rotational symmetry or no rotational symmetry, high airtightness can be obtained.

[0159] In the above-described embodiment and modified examples, the pressing ring 21A and the auxiliary pressing portion 21B are described as being provided on the bottom surface of the flange portion 13B having the protrusions 13C and 13D and covered with metal, but the present invention is not limited thereto.

[0160] For example, Fig.10 As shown, the bottom surface of the flange portion 13B may be entirely or partially flat, and a metal layer having a protrusion functioning as the pressing ring 21A or the auxiliary pressing portion 21B may be provided on the bottom surface. Fig.10This is a cross-sectional view showing the second embodiment, but the same is applicable to the first embodiment. The cross section of the convex portion is not limited to a semicircular shape, but may be a rectangular shape, a trapezoidal shape, or an inverted triangle (V-shape).

[0161] In addition, except for the cases where special description is given, the above-mentioned semiconductor materials, metal materials, numerical values, etc. are illustrative and are not to be interpreted as limiting. In addition, in this specification, the term "circular ring" includes an elliptical ring, an oblong ring, an oval ring, etc., and the same applies to a circle, a sphere, etc. In addition, the term "rectangular" includes a square, a rectangle, and shapes with chamfered corners.

[0162] As described above in detail, according to the present invention, it is possible to provide a semiconductor device having high bonding properties and high airtightness and having high environmental resistance even in a harsh environment such as humidity, which has high reliability and long service life.

Claims

1. A semiconductor light emitting device, comprising: Semiconductor light emitting element; a substrate, which carries the semiconductor light emitting element and has a substrate bonding surface covered by a substrate metal layer; as well as a light-transmitting cap having a window portion for transmitting the radiated light of the semiconductor light-emitting element and a flange portion with a circular inner edge, the light-transmitting cap having a space for accommodating the semiconductor light-emitting element, and the light-transmitting cap being sealed and joined to the substrate, The flange portion has a flat portion and a convex portion protruding from the flat portion at a center portion in a width direction of the bottom surface. The flange portion has a flange joint surface, and the flange joint surface includes: a pressing ring, which is a metal layer covering the convex portion, and is a circular annular convex portion concentric with the inner edge of the circle; an inner side joint area, which is a metal layer covering a flat portion on the inner side of the pressing ring; and an outer side joint area, which is a metal layer covering a flat portion on the outer side of the pressing ring. For the metal layer on the surface of the substrate metal layer and the flange joint surface, the substrate metal layer and the top of the pressing ring are joined together by a joining component at a certain interval, and the substrate metal layer is joined to the inner joining area and the outer joining area in a manner to form a strip-shaped airtight structure.

2. The semiconductor light emitting device according to claim 1, wherein: The flange joint surface has a circular ring shape, The pressing ring is arranged along a concentric circle which is concentric with the circular ring of the flange joint surface.

3. The semiconductor light emitting device according to claim 2, wherein: The pressing ring is provided along the concentric circle having a circumference of a center of a width of the circular ring of the flange joint surface.

4. The semiconductor light emitting device according to claim 2 or 3, wherein: The pressing ring has a semicircular shape, a rectangular shape, or a trapezoidal shape in a cross section perpendicular to the circumference of the concentric circle.

5. The semiconductor light emitting device according to any one of claims 1 to 3, wherein: The top of the pressing ring and the substrate metal layer are bonded together with a certain gap in between over the entire circumference of the top of the pressing ring.

6. The semiconductor light emitting device according to any one of claims 1 to 3, wherein: The top portion of the pressing ring is in direct contact with the substrate metal layer over the entire circumference of the top portion of the pressing ring.

7. The semiconductor light emitting device according to any one of claims 1 to 3, wherein: The flange joint surface has an auxiliary pressing ring, which is a circular annular convex portion that is concentric with the pressing ring and protrudes from the flat portion, and has a diameter larger than that of the pressing ring.

8. The semiconductor light emitting device according to any one of claims 1 to 3, wherein: The flange joint surface has a rectangular outer edge, The flange joint surface further includes an auxiliary pressing portion, which is a convex portion provided on a diagonal line of the flange joint surface and outside the pressing ring and protrudes from the flat portion.

9. The semiconductor light emitting device according to claim 8, wherein: The protruding height of the auxiliary pressing portion is smaller than the protruding height of the pressing ring.

10. The semiconductor light emitting device according to claim 8, wherein: The auxiliary pressing portion is composed of a plurality of auxiliary pressing elements, and at least one of the plurality of auxiliary pressing elements is located on the diagonal line.

11. The semiconductor light emitting device according to claim 10, wherein: The plurality of auxiliary pressing elements are arranged outside the pressing ring and located on a concentric circle of the pressing ring.

12. The semiconductor light emitting device according to any one of claims 1 to 3, wherein: The semiconductor light emitting element is an aluminum nitride-based light emitting element.

13. The semiconductor light emitting device according to claim 12, wherein: The semiconductor light emitting element is a light emitting element that emits ultraviolet light with a wavelength of 265 to 415 nm.

14. The semiconductor light emitting device according to any one of claims 1 to 3, wherein: The light-transmitting cap is made of quartz glass or borosilicate glass.

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